next the hunt for jimmy hoffa. >> a tip could crack a cold case open. where they are searching today. >>> shooter opens fire at a sign company in minneapolis before turning the gun on himself. details coming up. >>> this morning the names of the first victims are being rehe'sed in the shooting in -- being released in shooting in minnesota >> reporter: tense scene s.w.a.t. team responded to again man who opened fire, killing four, including the company's founder and then himself. >> i can confirm the suspect, the shooter is dead from a self-inflicted gunshot wound. >> reporter: this morning, police are trying to term if the shooter was a disgruntled worker. four were transported to the hospital, three in critical, fourth had minor injuries. it was a terrifying scene when police responded to the shooting around 4:30 yesterday afternoon. >> it appears to be multiple agencies, local and federal. >> reporter: tactical teams surrounded the building, evacuating people and swarmed the residental neighborhood people headed home from work saw their street become